// Copyright 2018 Google Inc. All Rights Reserved.
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//
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// Use of this source code is governed by a BSD-style license
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// that can be found in the COPYING file in the root of the source
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// tree. An additional intellectual property rights grant can be found
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// in the file PATENTS. All contributing project authors may
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// be found in the AUTHORS file in the root of the source tree.
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// -----------------------------------------------------------------------------
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#ifndef WEBP_DSP_QUANT_H_
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#define WEBP_DSP_QUANT_H_
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#include "src/dsp/dsp.h"
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#include "src/webp/types.h"
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#if defined(WEBP_USE_NEON) && !defined(WEBP_ANDROID_NEON) && \
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!defined(WEBP_HAVE_NEON_RTCD)
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#include <arm_neon.h>
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#define IsFlat IsFlat_NEON
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static uint32x2_t horizontal_add_uint32x4(const uint32x4_t a) {
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const uint64x2_t b = vpaddlq_u32(a);
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return vadd_u32(vreinterpret_u32_u64(vget_low_u64(b)),
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vreinterpret_u32_u64(vget_high_u64(b)));
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}
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static WEBP_INLINE int IsFlat(const int16_t* levels, int num_blocks,
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int thresh) {
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const int16x8_t tst_ones = vdupq_n_s16(-1);
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uint32x4_t sum = vdupq_n_u32(0);
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for (int i = 0; i < num_blocks; ++i) {
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// Set DC to zero.
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const int16x8_t a_0 = vsetq_lane_s16(0, vld1q_s16(levels), 0);
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const int16x8_t a_1 = vld1q_s16(levels + 8);
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const uint16x8_t b_0 = vshrq_n_u16(vtstq_s16(a_0, tst_ones), 15);
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const uint16x8_t b_1 = vshrq_n_u16(vtstq_s16(a_1, tst_ones), 15);
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sum = vpadalq_u16(sum, b_0);
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sum = vpadalq_u16(sum, b_1);
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levels += 16;
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}
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return thresh >= (int32_t)vget_lane_u32(horizontal_add_uint32x4(sum), 0);
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}
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#else
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#define IsFlat IsFlat_C
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static WEBP_INLINE int IsFlat(const int16_t* levels, int num_blocks,
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int thresh) {
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int score = 0;
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while (num_blocks-- > 0) { // TODO(skal): refine positional scoring?
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int i;
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for (i = 1; i < 16; ++i) { // omit DC, we're only interested in AC
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score += (levels[i] != 0);
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if (score > thresh) return 0;
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}
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levels += 16;
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}
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return 1;
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}
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#endif // defined(WEBP_USE_NEON) && !defined(WEBP_ANDROID_NEON) &&
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// !defined(WEBP_HAVE_NEON_RTCD)
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#endif // WEBP_DSP_QUANT_H_
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